If you have looked closely at the eyes of different animals, you will notice their pupils come in various shapes: round, vertical or horizontal ovals or crescents. Scientists now think they know the reason behind the shape of some animals’ pupils. There is diversity in shape because it depends on how big the animal is and whether it’s a predator or prey. It also relates to their view of the horizon. Listen to hear more about the new discovery and what it can tell us about animals and evolution.